Last spring, among the usual elementary school reminders about theme weeks and illicit peanut butter snacks (WE ARE A NUT FREE CAMPUS!!) an email popped up that gave me pause. My kindergartner would be weighed in school, it said, and I could click on a link to opt her out.

　　It gave me the ick. I’d paid attention to young women like Mary Cain and members of college cross-country teams speaking out against weigh-ins and body shaming in sport, and how the practice damaged their mental and physical health. That’s different from a kindergartner stepping on a scale then running back to recess, but I know how little minds absorb everything. I didn’t want my daughter to think her school cared about her weight.

　　Neither, it turns out, did our home state. In January 2022, California’s Department of Education suspended the body mass index reporting it had required since 1996 as part of a fitness test. (BMI, calculated from height and weight, is often used as a proxy for body fat composition.) The state also axed collecting several movement-based measurements that, along with gender, height, and age, had been used to give kids “fitness report cards,” citing concerns about mental health, accessibility, and gender equity. Every measure, except overall participation rates, was put on hold pending the outcome of a large study the state commissioned to explore potential best practices for school fitness testing.

　　Then, in March 2023, the California Department of Education dropped a 193-page report skewering school fitness testing as it’s been conducted for the past 25 years. In the report, experts in fitness, adaptive physical education, body image, and gender identity rejected the nation’s leading fitness evaluation. And so California became the first state to seek an answer to a simple and important question: What is the point of fitness testing?

　　Today, more than 10 million kids in over 20,000 schools across the U.S. take a test called Fitnessgram annually. It’s been California’s official assessment since 1996. It’s also used in New York City, the country’s largest school district, and it’s the official assessment of the Presidential Youth Fitness Program, the current iteration of more than six decades of federal initiatives targeting youth fitness.

　　Created by the Cooper Institute, a Dallas-based health nonprofit, the test is made up of various activities like a one-mile run, pushups, and the sit-and-reach to determine muscular strength, endurance, and flexibility, and aerobic capacity. There’s also a weigh-in component to measure body composition through BMI, and it is this measurement, in particular, that’s most often used to shape public policy, influencing everything from city-wide free school lunch programs to the length and number of movement breaks kids get throughout the school day.

　　The main idea behind the testing, says Dr. Weimo Zhu, who is on the advisory board for Fitnessgram, is “what you measure is what you get.” Fitnessgram benchmarks, called “Healthy Fitness Zones,” are national standards set by age and gender, and are meant to inspire kids to be active.

　　“The standard isn’t to punish the kids,” Zhu says. It’s to tell them if they need to take action to improve their health and fitness. Without it, he argues, kids won’t know the goal behind being fit, implying that maintaining a certain BMI range, strength, aerobic capacity, and range of motion, is the goal.

　　But in the decades since Fitnessgram was first implemented, the scientific understanding of BMI’s relationship to health has progressed, and American culture has changed. Instead of physical measurement, many educators and politicians have become more concerned with inclusivity and kids’ mental health. “We’re focused on making sure schools are safe and inclusive for all kids,” says Cheryl Cotton, California’s deputy superintendent of public instruction.

　　Cotton also noted that the final concern triggering California’s legislative report involved BMI, school weigh-ins, and mental health. “A lot of researchers at universities across the state and the nation were really digging into the issue of body shaming.” Those factors put fitness testing in California legislators’ crosshairs.

　　Fitnessgram standards, the lawmakers believe, aren’t inclusive. The Cooper Institute is in the process of incorporating the Brockport Fitness Assessment, the most widely used fitness assessment for kids with disabilities, into its evaluation. But as of November 2023, the Fitnessgram test provided no benchmarks for those students. The test defines different Healthy Fitness Zones for girls and boys, but not for nonbinary kids, an issue that catalyzed California’s study after the state passed the Gender Recognition Act in 2017, allowing residents to identify as nonbinary on state documents. (New York enacted a similar law in 2021.)

　　In 2018, California asked The Cooper Institute to provide performance standards for nonbinary students, and the Institute partially complied. “With a push, Fitnessgram added a nonbinary option,” Cotton says, but it wasn’t equitable. Students who chose nonbinary would get a personal score, but couldn’t be included in annual reporting because the Institute wouldn’t create nonbinary benchmarks. Instead, the Institute published a position statement from their advisory board asserting that results are most accurate using sex at birth, though teachers or parents could decide which gender identity would be most appropriate. (When reached for comment, Fitnessgram shared a statement with Outside reiterating this position.)

　　In 2005, a landmark report titled Preventing Childhood Obesity was published. It was commissioned by the federal government and edited by a former CDC director; the report has been credited with launching annual student BMI assessments nationwide.

　　Around the report’s debut, the language surrounding national interest in kids’ fitness shifted. It already had morphed in the seventies from concerns about military preparedness toward general health and disease prevention. But now, in a rejiggering of combat jargon, fitness was becoming a weapon in a war on obesity.

　　Instead of fighting foes abroad, school health and fitness programs would prepare kids to tackle fatness, the “enemy within,” as it’s been dubbed in studies and scientific papers. BMI became public health’s favored metric used to do things like monitor and adjust kids’ health and fitness programs across the country.

　　The state of New York has the nation’s most robust BMI monitoring program, which was created in 2007 and operates through a partnership between the school system and the state’s public health department. State law requires that 50 percent of all public schools in New York conduct surveys annually. New York City runs its own BMI monitoring program, separate from the state’s, using Fitnessgram BMI data.

　　Around the same time, several states including Massachusetts, Texas, West Virginia, Florida, Maine, Arkansas, New Mexico, Pennsylvania, and Georgia, also passed laws requiring BMI recording in schools. Other states gather childhood obesity information via phone or mail surveys or through local health programs, such as those targeting low-income mothers. Or they rely on an annual national health and nutrition survey for a glimpse into youth obesity trends.

　　But in recent years, scientists have found substantial evidence that children’s BMI is a poor predictor of future health—and even of current body fat, especially in children younger than nine. “Even in the ‘overweight’ category, it’s not necessarily predictive of poor metabolic health,” says Dr. Hannah Thompson, an animated Berkeley professor who explores how youth physical activity can improve health. “Cardiovascular fitness is.

　　Kids are naturally intuitive eaters, and “we disrupt that with messaging that weight equals health,” says Alisa Dodds, a registered dietitian and senior lecturer at Loyola Marymount University. Forming strong social connections, regular movement, and eating a variety of foods, she says, are behaviors associated with positive long-term health outcomes. “Weight is not a behavior.”

　　It’s also not linked to academic performance, nor has measuring BMI over the past two decades made kids thinner. (At best, it’s slowed the rate at which child obesity is increasing.) Weight is highly correlated with genetics and socio-economic status, two things kids have no control over.

　　Meanwhile, kids’ mental health has emerged as a primary concern, a crisis the pandemic exacerbated and that social media can fuel. In 2021, the American Academy of Pediatrics declared kids’ mental health a national emergency, noting that suicide is the second leading cause of death for youth ages 10 to 14. As of 2020, guns, cars, and drug overdoses are the top three leading causes of death in kids under 20, with heart disease and chronic respiratory disease—two issues often brought up in relation to high BMI—in eighth and tenth places.

　　Perhaps unsurprisingly, the very act of weighing kids in school can harm their mental health. Thompson served as an expert panelist in the California study and also as a researcher on a 2021 study, published in JAMA Pediatrics, that found that elementary and middle school students who had been weighed in school were less satisfied with their bodies than those who hadn’t been weighed. It’s another point in a spate of recent studies challenging BMI’s relevance to overall health.

　　Exercise is part of the solution for improving mental health. In some cases, it can be as effective as drugs at treating depression, and it’s a powerful tool for managing anxiety. Daily exercise is linked to better grades, memory, and concentration. There are many compelling reasons besides body size to justify school fitness programs. Nevertheless, Fitnessgram published a position statement in 2020, doubling down on body composition as a vital metric, even as California’s researchers and legislators were questioning its utility.

　　“PE is not supposed to impact BMI,” says Thompson. “The whole idea of physical education—apart from recess or other physical activity opportunities—is to help younger students build the foundation and skills to go on and be active later in life.”

　　My kindergartner wasn’t, in fact, going to be weighed in school as part of state fitness testing, but for our local health department. It’s used BMI since 2007 to track the effectiveness of several school-based health initiatives, including a garden and nutrition program, and morning exercises. I met with administrators to ask them to stop the weigh-ins, showing them that our state had suspended BMI reporting—and every other metric associated with Fitnessgram testing—out of concern for kids’ mental health, pending the results of the legislative report. They were open to using a different metric to guide their programming. But they couldn’t think of one.

　　Every expert I talked to, from epidemiologists to physical education teachers, is in favor of some form of fitness testing, because they use the metrics to design programs, evaluate their efficacy, identify areas of need, and track student progress. Public health departments run on metrics. Fitness tests are, “for lots of states, the only source of state-wide data we have on youth health,” Thompson says.

　　BMI data from Fitnessgram testing in New York City allowed researchers to link socioeconomic status with weight. Fitnessgram data also has helped researchers see that kids’ aerobic fitness tends to decline from lower school to high school. And when physical education programs stop testing, says Fran Meyer, executive director of the Society of State Leaders of Health and Physical Education, teachers and administrators can lose accountability for ensuring kids get that active time. “The focus on fitness diminishes,” she says, when progress can’t be measured.

　　But when the goal of physical education is to instill a lifelong love of movement, progress isn’t just physical. It’s not a math test, with a clear right, wrong, and class average. Test design must be sensitive to the fact that a kid’s body exists at the intersection of many factors, including culture, genetics, mental health, and socioeconomic status. Not every kid is motivated by comparison. Not every kid has the same opportunities for safe movement outside of school, or easy access to nature and whole foods.

　　So, California set out to reassess the point of physical education and school fitness programs. Only then could the state identify appropriate measurements for its students, ones that take into consideration the complex nature of health and the varied resources available to individual children.

　　Fitnessgram’s advisory board believes it’s put together the most accurate, comprehensive measurement of student fitness in a way that’s simple enough for schools to execute routinely. The California report, however, calls for measuring individual performance over time rather than comparing results against national standards. It also proposes eliminating BMI in favor of objective measures of aerobic capacity and cardiovascular fitness.

　　“Cardiorespiratory fitness is far more predictive of mortality than BMI,” Thompson says, though she couldn’t immediately come up with a simple way to gauge it. And simplicity is key when assessing thousands of wiggly kids.

　　Expert panelists cited in the California report suggested using wearable devices, like a FitBit, to more directly measure cardiovascular fitness, like VO2 max (the maximum amount of oxygen your body can use during exercise). Wearables can also approximate allostatic load, the amount of chronic stress in the body, through heart rate variability, the variation in the time interval between heartbeats. These metrics are not all perfectly inclusive, and take more time to gather BMI, but they’re a promising start.

　　“Health interventions can be done without using weight-loss as a goal,” Dobbs says. “It’s about being aligned with health-promoting behaviors versus a number on the scale.”

　　New York City is considering cutting their BMI program—the most comprehensive in the country—entirely, Thompson says. The move would signal that health officials are ready to move on to something different, though that may not happen soon. “We are always reviewing our processes to determine whether they are the best way to assess and promote student health, which is what we’re doing now,” a representative from New York City’s Department of Health and Mental Hygiene wrote in an email.

　　In California, legislators will review the fitness testing report and decide if they’ll move forward with recommendations, like allotting money toward developing the state’s own accessible and equitable test. “All of this work ties into that inclusive conversation, not just around physical fitness testing,” Cotton says, “but around our curriculum, and making sure our teachers understand our kids and have evidence-based strategies to really support them.”

　　Meanwhile, Fitnesgram’s 12-member advisory board continues to meet annually in an effort to improve the assessment, an act that shows measurement is not static. Fitnessgram can change. What metrics will reign supreme in the next chapter of kids’ fitness isn’t yet clear.

　　“It’s a huge challenge,” Dr. Weimo Zhu says, of motivating kids to become lifelong lovers of fitness—and of finding the metrics that best promote that journey. “We’ll keep working on it.”